1. Field of the Invention
The invention relates to a self-propelled construction machine, in particular a road milling machine or a slipform paver, comprising a chassis which comprises front and rear wheels or running gears in the working direction, a machine frame supported by the chassis, a drive device for driving the front and/or rear wheels or running gears, and a steering gear for steering the front and/or rear wheels or running gears such that the construction machine can carry out translational and/or rotational movements on the terrain. In addition, the invention relates to a method for visualising the working environment of a construction machine moving on the terrain, in particular a road milling machine or a slipform paver.
2. Description of the Prior Art
Various types of self-propelled construction machines are known. These machines include in particular the known slipform pavers or road milling machines. These construction machines are distinctive in that they comprise a working device for installing structures on the terrain or for modifying the terrain.
The slipform pavers comprise a device for moulding flowable material, in particular concrete, which device is also known as a concrete trough. Structures of various designs, for example guide walls or gutters, can be produced using the concrete trough. In the case of road millers, the working device comprises a milling roller equipped with milling tools, by means of which material can be milled off the road surface in a predefined working width.
EP 2 336 424 A2 describes a self-propelled construction machine comprising a unit for determining data describing a target curve in a reference system independent of the position and orientation of the construction machine, and a control unit which is configured such that a reference point on the construction machine moves along the target curve from a predefined starting point at which the construction machine has a predefined position and orientation on the terrain.
EP 2 719 829 A1 discloses a method for controlling a construction machine, in which the data describing a target curve are determined in a reference system independent of the position and orientation of the construction machine by means of a measuring device (rover) on the terrain and are input into a working memory of the construction machine. The known method makes it possible to more accurately control the construction machine without great complexity in terms of measurement.
When planning a construction project to be carried out using the known slipform pavers or road millers, the problem arises that objects already existing on the terrain, such as water outlets, hydrants or manhole covers, must be taken into account. For example, the structure should not be located on a water outlet, or the region of the terrain in which, for example, a hydrant or manhole cover is to be found, should not be modified.
In order to take into account objects present on the terrain, intervention in the machine control is necessary, which may be carried out manually.
The milling roller of a road milling machine must, for example when travelling over a hydrant, be raised from a predefined position relative to the surface to be worked, taking account of a safety distance within a path distance dependent on the dimensions of the hydrant. In practice, however, the machine operator cannot identify the exact position of the hydrant at the level of the milling roller, since the milling roller is located below the cab. Therefore, in practice, the position of a hydrant on the terrain is marked by visible lines, which can be identified by the machine operator or another person. In practice, however, marking objects present on the terrain is disadvantageous. Firstly, marking the objects requires an additional work step. In addition, it is difficult to mark the lines exactly at right angles to the direction of travel. Moreover, the lines are impossible or difficult to identify in the dark. Furthermore, marking the objects is difficult when it is raining. Due to the inaccuracies, it is therefore necessary to select a relatively large safety distance which requires significant reworking.
In the case of a slipform paver, the same problem arises when a structure is to be installed which is to be located not on, but rather beside, objects present on the terrain. If, for example, the structure is to extend along a curb, water outlets beside the curb cannot be identified by the machine operator if the water outlets are located immediately in front of or beside the machine. In the case of a slipform paver, an additional difficulty is that it is not possible to correct the path course at short notice if it is identified only shortly before the water inlet that the planned path course extends over said inlet.
In order to automatically control the construction machine while also taking account of objects present on the terrain, it is possible in principle to determine the shape and the location of the objects on the terrain. If the shape and location of the objects are known, intervention in the machine control can also occur automatically; for example, the milling roller of a road milling machine can be automatically raised when travelling over the object. However, this requires an exact determination of the shape and location of the object, for example the hydrant, in relation to the coordinate system in which the construction machine is to move. Otherwise, the hydrant or the construction machine may be damaged.